Get the unwrap field from a s-char-char.
This is an ordinary field accessor created by fty::defprod.
Function:
(defun s-char-char->unwrap$inline (x) (declare (xargs :guard (s-char-p x))) (declare (xargs :guard (equal (s-char-kind x) :char))) (let ((__function__ 's-char-char->unwrap)) (declare (ignorable __function__)) (mbe :logic (b* ((x (and (equal (s-char-kind x) :char) x))) (nfix (std::da-nth 0 (cdr x)))) :exec (std::da-nth 0 (cdr x)))))
Theorem:
(defthm natp-of-s-char-char->unwrap (b* ((unwrap (s-char-char->unwrap$inline x))) (natp unwrap)) :rule-classes :rewrite)
Theorem:
(defthm s-char-char->unwrap$inline-of-s-char-fix-x (equal (s-char-char->unwrap$inline (s-char-fix x)) (s-char-char->unwrap$inline x)))
Theorem:
(defthm s-char-char->unwrap$inline-s-char-equiv-congruence-on-x (implies (s-char-equiv x x-equiv) (equal (s-char-char->unwrap$inline x) (s-char-char->unwrap$inline x-equiv))) :rule-classes :congruence)
Theorem:
(defthm s-char-char->unwrap-when-wrong-kind (implies (not (equal (s-char-kind x) :char)) (equal (s-char-char->unwrap x) (nfix nil))))